There's no BMI requirement for any specific wls procedure. The type of surgery is a medical decision made between the Dr and patient, not the insurance company. Most insurance won't cover wls unless you have a 40 bmi or other medical issues like pre diabetes etc.
I had a 39 to 40 BMI at 287 lbs. I choose the Sadi DS over the traditional Hess DS, RNY, VSG or Lapband after disucssing my goals with my doctor. My criteria was to lose all the weight, keep it off and be able to eat normally eventually. All of them are true for me today (9 years later) but I also do my part with at least trying to mostly eat well, and getting daily exercise.
It's important to note that wls creates an imbalance in your body and you have to make adjustments including the vitamins, eating, accepting loose skin, bloating and gas issues with bad food choices, etc.
FYI - It's not an easy journey and takes time. If you make the commitment, it's worth it. Below is my journey and my almost 63 year old body 9 years post Sadi.